Every year, ambitious young bands find new waysfascinating, puerile, ingeniousto play the Internet, and in 2011, one of the most captivating, effective ways to do so involved near-silence. A cluster of breakthrough bands, WU LYF and Unknown Mortal Orchestra among them, caused a huge publicity ripple online by pointedly refusing to exist thereor deciding to have an online presence so cryptic as to frustrate any desire for even the most basic information. In this scenario, a band's lack of Google hits are a direct measure of its tantalizing mysteriousness. If the Internet is a musical instrument, this was its version of John Cage's "4:33."

In WU and UMO's cases, the trick succeeded wildly. WU LYF had already built a passionate local following in Manchester on the strength of their ragged, fervent indie rock. But by refusing to do mundane thingsanswering telephone calls from Michel Gondry, parting with free copies of their demo, sustaining a web sitethey kicked the speculative frenzy up into high gear. The Portland psych-rock weirdos Unknown Mortal Orchestra, meanwhile, were less prickly and rebellious, but in the earliest days they were nothing more than a serenely inscrutable Bandcamp page full of ear-grabbing songs. Discovering anything further about their creators proved nearly impossible until months later.

This faux-cultivation of mystery makes sense for bands looking for quick and easy ways to distinguish themselves: In an era of constant, ceaseless glut, set yourself apart by being hard to find. It's a marketing technique with real-world echoes in 21st-century speakeasies, or nightclubs that you need a password to enter. There's an easy exclusivity grab to being "anonymous," and cachet to be gained from appearing "above it all," that is as old as culture itself.

However, there's a catch: for the anonymity gimmick to pan out for you, your music has to feel like a revelation worth waiting for. UMO and WU LYF played the card successfully because that mystery turned out to feed neatly back into their music. WU LYF's dark debut Go Tell Fire to the Mountain, with its gasped, unintelligible exhortations, felt like recently unearthed caveman liturgical music, while UMO's eerily out-of-time self-titled debut appeared to have wandered, beaming, out of the desert, origins unknown.